Historically, new facts and/or hypotheses bearing on the etiology, pathogenesis, and/or prevention of disease have often been discovered by epidemiological investigation of previously unstudied population with distinctive genetic and cultural attributes. Mexican Americans are such a population. There is reason to believe that this population developed a high prevalence of obesity and diabetes mellitus as it underwent a historic change from food scarcity to relative food abundance. There is also evidence to suggest that this situation may now be changing, i.e., that there may be a "descending limb" to the rising affluence, rising obesity and diabetes curve. We plan to study the distribution of "diabetic pattern" (i.e., glucose intolerance, obesity, hypertriglyceridemia and perhaps also alpha-lipoprotein levels) and other cardiovascular risk factors in 2400 Mexican Americans and 1600 Anglos randomly selected from 6 census tracts in San Antonio, Texas. These tracts have been chosen so as to represent three socially and ethnically diverse regions of the city: a highly traditional, almost exclusively Mexican American neighborhood ("barrio"); an ethnically integrated area ("bicultural"); and a predominantly Anglo region ("suburbs"). We postulate that Mexican Americans will be progressively move acculturated to mainstream U.S. culture as one mores from the barrio to the suburbs, thus enabling us to test our basic hypothesis that "diabetic pattern" cardiovascular risk factors vary inversely with degree of acculturation. Cardiovascular risk factors to be measured include glucose intolerance, obesity, lipids, lipoproteins, blood pressure, and smoking history. Acculturation-related variables include generational status in the U.S., culture of upbringing, language patterns, familism, social mobility, and dietary patterns. We will also evaluate the possibility that a criterion for diagnosing diabetes based on glycosylated hemoglobin may be superior to presently available criteria for use in epidemiological studies.